A NIR dual-functional chemosensor for monitoring the redox level and micro-viscosity during cuproptosis process

A recently characterized copper-mediated cell death pathway, cuproptosis, is distinguished by mitochondrial dysfunction, elevated reactive oxygen species, and protein aggregation. Accurate assessment of reactive chemical species and shifts in the cellular microenvironment during this process is essential for elucidating its underlying mechanisms. Herein, we describe the rational construction and application of a bifunctional fluorescent sensor, YTO, engineered to simultaneously monitor hypochlorous acid (HOCl) and intracellular microviscosity through discrete fluorescence channels. This probe exhibits remarkable specificity for HOCl, a fast response kinetics, a low limit of detection (16 nM), and excellent stability under physiological conditions. The viscosity-sensing capability operates via a twisted intramolecular charge transfer (TICT) mechanism, whereas HOCl recognition relies on oxidation-triggered suppression of intramolecular charge transfer (ICT). Crucially, YTO enables real-time imaging of both oxidative stress and viscosity fluctuations during copper-induced apoptotic processes. Our findings reveal that cuproptosis leads to elevated oxidative stress levels and underscore the critical involvement of glutathione (GSH) in regulating this cell death modality when sufficient intracellular Cu(II) is present. This dual-parameter probe constitutes a valuable tool for investigating the complex interplay between copper homeostasis, redox state, and microenvironmental parameters in living systems.